It has been known to pivot a blanking die in an oscillatory manner between angularly displaced cutting positions wherein the die cuts through sheet material, such as steel, in order to form trapezoidal blanks. Trapezoidal blanks are particularly desirable when forming components having a tapered configuration, such as an automobile hood, because they reduce the amount of material which must be trimmed off and discarded as scrap, thereby realizing a savings in material and manufacturing costs. Some known assemblies have utilized air cylinders to drive the blanking die about its pivot axis. However, utilizing air cylinders is relatively slow and it is difficult to control the angular displacement of the blanking die with a desirable degree of precision.
Other types of assemblies utilize a servomotor and gear the servomotor to a vertically extending turnable shaft which is coextensive with the pivot axis of the die. An example of such an assembly is disclosed in U.S. Pat. No. 4,942,797 to Nakamura. In the assembly of the '797 patent, a series of intermeshed gears are used to translate the rotation of the servomotor into turning of the turnable shaft and pivotal movement of the die. Over time, the teeth on these gears may wear down. Furthermore, utilization of a plurality of intermeshed gears increases the complexity and cost of the assembly and its maintenance.